1. Field of the Invention
This invention relates to production from a single, printable sheet of paper or the like, of a letter form, which serves as both letter and envelope.
2. Description of the Prior Art
Letter forms of this type consisting of a single sheet and, when folded, made up of two or several leaves lying one atop another, joined together to form a self-contained letter/envelope are known, for example, from Swiss Patent No. 609,634 and U.S. Pat. No. 3,482,780. In these types of letter form, the inner side of the sheet is printed with information and a mailing address. The sheet is then folded once or twice and the two or three sheet-parts are stuck together along their edges. With the exception of the address, the lettering on the inner side of the sheet is thus covered. The latter is visible through a window. The address area with the address of the addressee, located on one sheet-part, and the window which is to be provided on the other sheet-part must therefore be arranged in such a manner that they lie opposite one another when the sheet is folded. The consequence of this is a lack of freedom in the choice of where the address area and window are to be arranged, especially if the position at which the address is to appear on a letter is governed by existing postal regulations.
Furthermore, the known letter forms consisting of two parts have the disadvantage that it is impossible to insert an enclosure between the folded halves of the sheet since this would obscure the address area, unless the enclosure is both too small to cover up the address area and also is secured so that it cannot slip in front of the address area.
It is an object of the present invention to provide a letter form giving greater freedom in the arrangement of the address area and the window than with known letter forms and with which there is no risk of the address being unintentionally covered by any enclosures inserted.
It is a further object of the present invention to provide a process which permits the production, in a simple manner, of such letter forms.
These and other objects are achieved by the article and process described herein and illustrated by the accompanying drawings.